The theorbo offers tremendous possibilities to composers. Its voice has something of the lute, the guitar and the harp, but it also has resources available on no other instrument. However, its extraordinary tuning and specialized notation can be off-putting. The following paragraphs are designed to give composers the information they need to compose effectively for the theorbo, and to write the resultant parts down in a mutually convenient way.

Timbre and VolumeThe theorbo produces a sound roughly comparable in volume to a classical guitar, but relatively stronger in the bass and weaker in the upper register. The exact timbre will depend on the individual instrument and on whether or not its player uses nails. Nails will produce a harder-edged attack, flesh will produce a softer-edged sound, which is not necessarily softer in volume. Because its voice is relatively soft in modern terms, the theorbo will not suit every musical situation. It combines especially well with voices, with other types of plucked instrument, with other historical instruments, of course, but also with smallish ensembles of almost anything if handled sensitively. It can even make an effective contribution to a symphonic score if the texture and orchestration are suitably light.

Range and tuningThe theorbo is normally tuned in A, but some players, especially in continental Europe, tune their theorbos in G. If you are writing for a specific player it would be advisable to check which tuning they use, otherwise the A tuning was historically more common, and is more widespread today.A typical theorbo has 14 courses, some fretted and some not, and a re-entrant tuning, which means that its fretted strings are not arranged in pitch order, as on a guitar or violin. Historically, the fretted courses were double (and are so indicated on the tuning chart below) but most modern players use single strings there.

The theorbo in A is tuned:

Its range is GG - a'. Some instruments will have a high b' but this is not usually very accessible.The theorbo in G is tuned a tone lower than the theorbo in A. Its range is FF - g'. Some instruments will have a high a' but this is not usually very accessible.

Chromatic capabilityHistorically, only the first six strings are fretted. Modern theorbos sometimes have more fretted strings but it is safest to assume only six. These strings (the ones preceding the double barline in my tuning examples) are chromatically fretted, like a guitar, and available notes range from the open string pitch to a minor 7th above.The 8 lower strings are diatonic only, and are typically tuned to the white notes of the piano keyboard. These can be adjusted for different keys - for example, the F string can be tuned to F sharp, the E string to E flat, etc. - but they cannot be retuned during playing. If you are not writing tonal music you could specify which notes you want in this register, but it is not advisable to tune these strings more than a semitone above or a tone below their normal pitch.

Locating and combining fretted notesThe theorbo's characteristic tuning means that many notes can be found in several places on the fingerboard, and the combinations are restricted only by the reach of the player's hand. The theorbo varies in size, but is basically a large instrument, so it is safest to restrict chords to notes falling within a 4-fret stretch, and to use even this stretch sparingly in the lower positions. A fingerboard map for a theorbo tuned in A with two re-entrant strings can be downloaded here.

Right hand techniquesThe strings are plucked somewhat like those of a guitar, but with two important differences. The hand is steadied by placing the little finger on the soundboard, which limits the flexibility of the ring finger. Also the thumb has to manage all of the unfretted basses, and frequently plays the fretted strings too. The terrifically high speeds which some classical guitarists can attain are not possible on the theorbo, partly because it is a much bigger instrument and takes longer to speak, and partly because most theorbo players pluck with the flesh of the fingertip, not with the nails, and this takes longer to register on a string. Typical textures are:-Plucked chords of two or three notes, including no more than one of the unfretted basses.-Spread chords of up to six notes (one note per string!) on the fretted strings. An unfretted bass string may be added. Chords can be re-iterated and rolled in a variety of ways. Chords lying on adjacent strings may also be brushed rapidly downwards with the thumb.-Running single line passage-work. This is best restricted to the fretted strings, which puts these lines in the baritone and tenor registers. Players will generally arrange the fingering so that as many notes as possible fall on different strings, giving a harp-like effect which we call 'campanellas'. Considerable speed is possible in these registers, especially if plucked notes are combined with left-hand slurs. Single lines on the unfretted basses need to be much slower, since these are all plucked by the thumb only.Strumming is possible, including elaborate strumming patterns borrowed from the baroque guitar, but the required notes within chords must lie on adjacent strings. Strumming is not always practical on very big theorbos, because the size of the body limits the movement of the player's arm.

Dynamic variationsThe right hand is also responsible for dynamics. A complete gradation of dynamic is possible, ranging from a mere whisper of sound to a strong fortissimo. To pluck loudly, the fingers require more registration on the strings, which means some speed must be sacrificed. Basically the theorbo can be played fast OR loud, but not both simultaneously.

Left hand techniquesLeft hand techniques on the theorbo are virtually the same as on the lute or the guitar, except that some allowance must be made for the longer string length and larger stretches involved. Note that the left hand stops only the top 6 strings of the theorbo: the low bass strings cannot be fretted, partly because they are too long to reach, and partly because there is no fingerboard directly under them.Slurs in both directions are very successful on the theorbo, but need to fall within the reach of the hand; a 4-fret stretch is the maximum practical reach. Slurs to or from an open string are possible from any fret on that string.Slides also work well, but need to be quite fast because of the instrument's limited sustain. Note that because of the theorbo's frets, these will sound as slurs rising or falling through several successive semitones, not as a smooth microtonal glissando.A huge variety of left hand ornaments is possible. Players expect to add a lot of left hand ornamentation - mordents, appoggiaturas and trills of various types - to the theorbo's historical solo repertory, so adding them in the context of a modern piece should cause no problems.Vibrato is regarded as an ornament in baroque music, not as an indispensible aspect of sound production, as it is on many modern instruments. It is effective on a theorbo but only with single notes, not with chords. Of course it can only be used on fretted notes, not on open strings. It is a subtle effect which works best on the upper frets (those nearest to the theorbo's body) but it can also work in lower positions. Although vibrato will slightly alter the pitch of a note, it is impractical to request extreme pitch-bending. This is only effective on theorbos with high actions (unpopular with many players!) and nylon strings. Gut strings are quite likely to break if you try this.

Non-historical and extended techniques

HarmonicsNatural harmonics (those occurring at the main node points of the strings) are quite effective on theorbos, especially those at the 12th fret (an octave above the open string) and the 7th fret (a twelfth above the open string). Artificial harmonics, of the kind commonly used on classical guitar, are not practical because they rely on moving the right hand along the string at 12 frets' distance from the stopping finger, and reaching this far around the theorbo's body is not always possible. Notating harmonics in theorbo music can be problematic, because many players will not have used them (they do not occur in the historical repertory). A verbal instruction in the score, explaining how you have notated them, may be advisable.

MicrotonesAlthough these are theoretically available, since the theorbo has movable frets, in practice they are rather difficult to use. Moving a fret affects all six fretted strings, which may not give the desired effect. Tying additional frets in between the normal ones is a possibility - I use this measure very frequently to obtain chromatic notes in some of the more extreme historical temperaments. However, these frets take time to set up, require some practice to use, and are only completely trouble-free on very large theorbos. On smaller theorbos (the majority today) the microtonal frets are simply too close together to fit a finger between them.

Non-western scale systemsApproximations to a variety of non-western scales can be achieved on the theorbo. Modes with western interval sizes but with non-tonal intervalic patterns can be very successful. Modes with non-western interval sizes, such as many Arabic modes which require three-quarter tones, are less successful, even with a shuffling of the frets, because the interval patterns do not always repeat at the intervals between open strings. Of the Javanese gamelan scales, a fairly good approximation of the pentatonic Slendro scale can be achieved simply by omitting certain notes of the western scale; however, the heptatonic Pelog scale simply does not work on a theorbo. I'm afraid I don't know anything about Indian scales and their feasibility on the theorbo. If you do, please get in touch!

Extended and avant-garde techniquesRather a limited palette here, I'm afraid. Theorbos are expensive and fragile instruments, and theorbo makers have long waiting lists. If you include techniques which require striking or scraping the theorbo (even with fingers), or putting anything in it or on it, you are likely to have difficulty persuading anyone to play your piece, simply because of the risk of damaging the instrument. Sliding things like bottlenecks or guitar slides along the strings doesn't work particularly well, because gut strings are relatively rough. Some dramatic timbre changes are possible. A muted pizzicato-like sound can be achieved either by fretting exactly on the frets, or by partially damping the strings near the bridge. Another effective way of changing the timbre is to thread a small piece of paper loosely between the strings, which can give a very striking buzzing effect, rather like a bray-pin harp. Some clarity of pitch is lost. This effect is quick and easy to set up, and only a few seconds are required to add or remove the paper. Different papers give different sound effects, and the exact positioning of the paper can also radically affect the sound. I'm sure composers will find other ways of using the theorbo, but if you are a composer thinking along these lines, please bear in the mind the extreme fragility of the instrument.

AmplificationComposers' thoughts frequently turn in this direction, partly because of the ability to cancel out disparities in the dynamics of different instruments, and partly because of the possibility of adding electronic effects. Amplifying a theorbo is easy and effective. The two main ways are via a free-standing microphone, or via a contact microphone fixed to the instrument. Free-standing microphones are often of higher quality than contact microphones, and leave the instrument completely untouched and the player unencumbered with cables. The disadvantages are that they are sometimes too sensitive to players' movements, and may pick up extraneous noises such as shuffling feet, creaky chairs and page turns. If you go for this option, the most successful place to put the microphone seems to be above the theorbo and slightly to the player's right, which is the way the theorbo will normally face. The optimum distance will depend on the microphone, but close-miking will pick up a lot of finger- and string-noise. With a contact microphone, the best place seems to be on the soundboard rim, a couple of centimetres from the edge and just to the bass side of the centre joint in the soundboard. Unfortunately this is also where many players will want to rest their right arm, so some care is needed to find a spot where the arm will not interfere with the microphone. I stick my microphone to the soundboard with a double layer of double-sided sticky tape. This needs to be removed by very slowly and gently pushing the microphone sideways, NOT by pulling upwards, which will tend to tear out bits of soundboard wood. The lead from the microphone will probably need to be tied to the theorbo's endpin, to stop the combined weight of the microphone, lead and plug from pulling the microphone off the soundboard. This microphone will only amplify sounds from the instrument, not from the player's feet, score or nearby colleagues, but the attached lead can be inhibiting. Also any movement of the cable may lead to crackling noises; good quality leads and plugs are essential.

NotationNotation is a particularly thorny issue. Historical theorbo repertory is written in either tablature (solo music), or figured bass (continuo parts). Present-day composers may not be familiar with either system, these notations may not suit the type of piece composers want to write, and some theorbo players are not fluent readers of other types of notation. If you are writing for a specific player it is worth checking what notations he or she is happy to read. If your composition is one which could be effectively put into tablature, many players will do this anyway for their own convenience, and may be willing to make a tablature part for publication. Intabulation (the process of writing a piece down in tablature) means that fingerboard locations of notes are specified, and players working from tablatures do not have the same freedom to choose their own fingerings that they would have when playing from staff notation. Therefore, if a tablature part is provided, it is useful to provide a staff notation part as well. This will also be useful to any other performers involved in the piece, who may not read tablature.Historical theorbo parts in staff notation are usually continuo parts which are mostly written on a single staff in the bass clef, with clef changes (typically into tenor or alto clefs) where the bass line is high. Some obbligato parts in operas and oratorios are written entirely in the alto or tenor clefs, using the highest register of the instrument. Today, since many theorbo players have been trained initially on the classical guitar, the octave treble clef is more widely read than the old-fashioned C clefs. A keyboard-style staff with treble and bass clefs is sometimes useful for wide-ranging parts, though a single staff is more compact and thus necessitates fewer page turns, which are awkward for the theorbo player. In general it is wise to avoid unusual clefs or layouts, to make sure that the intended octave is clearly specified, and to add verbal instructions for any unusual techniques which your piece may require.Continuo accompaniment (which virtually all theorbo players can do) is essentially an improvised art within a fairly confined structure. The composer specifies the bass line and sometimes some or all of the harmonies to be played above it, but the voicings of the chords, sometimes the harmonies themselves, and the entire texture of the accompaniment are decided by the player and will be at least slightly different in every performance. Theorbo players are therefore quite used to taking part in the compositional process to some extent, but generally within the framework of musical language from around 1600 to around 1750. A modern aleatoric or partly aleatoric work may require detailed verbal explanation, and theorbo players may be quite unused to improvising in a modern idiom.

It is helpful to the player to indicate the required tuning of the diapasons at the head of the piece. Cues to other parts, verbal instructions regarding tempi and other essential performance information, are all welcome and helpful.If you are using the theorbo to accompany song, it is extremely helpful for the player to have the full text of the song and the singer's part, with a translation into a widely-known language, if it is not already in one.